Skinny Dippin's Tank Cleaning: A Trip Report

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Tom.B

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Vessel Name
Skinny Dippin'
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Navigator 4200 Classic
I figured I would share our tank cleaning experience in case anyone else is planning on having it done.

When I decided to have it done, I called a local boatyard I was interested in using for the first time. Kenny Bock at Bock Marine basically said, "Just call Craig Shrek. He's who I would call to do it anyway." So, while curious why Kenny wanted out of the chance to take my money, I called Craig Shrek with Eastern Marine Diesel (or EMD Fuels... EMD Fuel System Service NC - Diesel Fuel Polishing North Carolina). Even over the phone, Craig was a wealth of information and very patient as I learned what I needed to know and asked questions. He was equally accommodating while we attempted to get the work scheduled at a time that worked well for both of us.

After a few back and forth attempts, we (well Bess, really) decided that it would be best for us to try and get it done in Beaufort, NC and incorporate it into our first summer cruising vacation. You see, he needs to be within 80' of the boat for his trucks hoses to reach us. He has an "agreement" with the Beaufort Town Docks where they will hold a spot on the bulkhead at the parking lot should he need it. Bess loves Beaufort and on Monday morning, after a few passing showers ended, Craig and Jed (his able-bodied assistant) arrived in Craig's custom designed fuel filtering and pumping truck and got to work.

Job one was for me to transfer all my fuel to one side. I carefully planned this process at a point when we were down to just about 15-20 gallons onboard. The truth is that we were low enough on fuel that I felt it would be best for me to move it all over to one tank before we left our home port and closed of the other to prevent gulping air. So honestly, step one was over before it started.

Step two was pull the access panel covers. Something that I was fearful to do alone as they are vertical. I mean, it's one thing to feel good about pulling and reinstalling a plate that holds back fresh water. It's a whole different thing to do it with a panel that hold back fuel. I didn't want to accept that liability.

It was a big moment with the panel came off. Was it going to be a complete mess? Would there be rust? Would this be a colossal waste of money? My heart was going 200 BPM when we finally pulled the plate off. Well, it was not as bad as I thought, but it was certainly time to get it done. There was a thick (3") layer of sludge in the tank's bottom. The tank is form-fitted to the hull (saddle tanks) with a gate valve at the lower-most and aft-most point. Every bit of that could find its way to the filter eventually.

One more note about the access plates: The gaskets were apparently a flat piece of rubber that covered the entire opening, however, the whole center section had deteriorated and was actually broken off and was sunk in the fuel tank. When Jed grabbed it, it practically turned to goo instantly. I'd bet that wasn't too good for the motor.

Step three was to start soaking up the muck. Jed did all the dirty work while Craig setup the truck. Jed used nothing but the oil pads you buy at West Marine. I'm not sure what I was expecting, but it was a surprise to see him use them. It didn't take long to see why. They worked very well. He got as much as he could reach. The two baffles were a bit of a problem, but the scrubbing process would get any remaining residue.

It took a few hours. I helped where I could, but there isn't room for more than one person at a time in my "engine room" :rolleyes:, so I would hand him tools, get him all setup, and then leave him to his work. He liked to talk and I know that if I stayed, I would extend the job by HOURS while he spilled his life story. Not that it wasn't interesting, I just feel bad about slowing people's work by fertilizing the conversation. Besides, talking to Craig outside was teaching me a LOT about fuel science.

The final step was to give the tanks a final cleaning with the scrubbing rig. two 2" hoses went into each baffled section of the tanks. My remaining fuel was scrubbed at 60 GPM. Craig manned the complex controls and closely watched the vacuum gauges to insure that there was actually progress being made. It took a couple of Racor 1000 filters and circulating fuel for over an hour per tank for Craig to feel they got it all.

After it was all said and done, the job's total time was about 6 hours. We felt that the fuel we used to scrub was really in no shape to keep. All it took was seeing it side by side with new. So he removed the remaining few gallons I had onboard and I bought 100 brand new gallons from the marina pumps. Not forgetting to mark exactly where 50 gallons in each tank comes up to on the sight tubes. :socool:

Final thoughts are this: It was the best $500 I have spent on the boat to date. It was needed and was not too far gone to have it be a 100% success. I also now have a much higher level of confidence in the boat beneath us and have reduced the chances of being stranded by this to nearly zero. Our steel tanks showed some VERY LIGHT pitting. Nothing to worry about and age appropriate. The quality time I spent with Craig went a long way in helping me better understand the fuel industry and I will highly recommend him to anyone in the area that needs fuel services. I paid in cash to help him keep more of it and Jed got a $20 tip for having to do all the sweaty work... :)

I hope this will help you should you need to same job in the future.

Later Dooooooodz,
Tom-

Here are a few pics of the process:
1) Starboard tank (before)
2) Port tank (before)
3) Jed "in the hole"
4) Bucket of gunk soaked oil rags
5) Distance from boat to truck
6) Scrubbing hoses
7) Scrubbing hoses II
8) Craig monitoring the truck
 

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Tom I enjoyed reading your post just because of your grasp of the language and your attention to detail. If you don't mind me asking what kind of work are you in or did you do. Oh yea, I'm glad the tank cleaning when well. Paul
 
Hi Tom and Bess,
That sounds like $500 well spent. You had a specialist do the job, it was fast and professional,and you have the assurance when out cruising that your tanks are restored to pristine condition.
To keep it that way, my diesel man taught me to start any fill by squirting some fuel into a glass jar before putting it in the tanks. Bubbles that remain are not bubbles but water.But you knew that. Happy Cruising. BruceK
 
I agree with your statement about the best $500 spent on the boat. Assurance and piece of mind are two things that go beyond price. I'm also sure you received far in excess of that value in education of fuel systems in that 6 hours.
 
I'm surprised that there would be access plates on the sides of the tank. I would expect them to leak, but apparently, if done properly, they do not.

My boat has just a couple inches of clearance between the top of the tanks and the bottom of the deck. No way to access through the top without cutting the deck.

I wonder if a professional like you used could cut access holes in the sides of the tanks and effectively seal them after cleaning the tanks.
 
Yes. He says they do it quite often. Although, I'd almost say that it would be worth a look to consider having a fiberglass craftsmen fabricate a panel to access your access plate. :)
 
I'm surprised that there would be access plates on the sides of the tank. I would expect them to leak, but apparently, if done properly, they do not.

My boat has just a couple inches of clearance between the top of the tanks and the bottom of the deck. No way to access through the top without cutting the deck.

I wonder if a professional like you used could cut access holes in the sides of the tanks and effectively seal them after cleaning the tanks.

Looks good Tom! :thumb:

We also have side tank access ports. Unfortunately only one per tank and its in the forward quarter. Our tanks (2) have 3 baffles each. Later this summer I'll be adding at least 2 more access ports per tank. I'll install these most likely.

http://www.fisheriessupply.com/productgroupdetail.aspx?cid=102234&keywords=Seabuilt

I've talked with 2 other owners who have added ports. One used a hole saw and the other used a jig saw. I'll let you know how it goes.

As far as sealing the tanks, I have been in ours and never had any leaks. I assume Tom had new gaskets cut from the correct material for his.
 
Yes. He says they do it quite often. Although, I'd almost say that it would be worth a look to consider having a fiberglass craftsmen fabricate a panel to access your access plate. :)

There are no access plates currently (that I know of). I don't think I could replace the fuel level sender without moving the tank. I've never tried, though.

The top of one tank is under a seating/storage area so cutting the deck wouldn't be a problem.

The other tank is under my newly installed AMTICO simulated teak and holly flooring so that will only be cut if the boat will no longer run. ;)
 
Looks good Tom! :thumb:

We also have side tank access ports. Unfortunately only one per tank and its in the forward quarter. Our tanks (2) have 3 baffles each. Later this summer I'll be adding at least 2 more access ports per tank. I'll install these most likely.

http://www.fisheriessupply.com/productgroupdetail.aspx?cid=102234&keywords=Seabuilt

I've talked with 2 other owners who have added ports. One used a hole saw and the other used a jig saw. I'll let you know how it goes.

As far as sealing the tanks, I have been in ours and never had any leaks. I assume Tom had new gaskets cut from the correct material for his.

Cutting with any type of saw will result in metal particles in the tank. That would concern me.
 
Cutting with any type of saw will result in metal particles in the tank. That would concern me.

While anything CAN happen, you would be surprised how few if any would actually land inside the tank with a couple of well placed magnets and bees wax. Especially if using a hole saw at slow rpm.
 
Cutting with any type of saw will result in metal particles in the tank. That would concern me.

The reason I want to install the inspection plates is to clean and line the tanks. The metal filings will (should) be gone with the sludge and thorough tank cleaning prier to coating. Even if a few filings are left behind I'm not sure they would cause any issues.
 
As far as sealing the tanks, I have been in ours and never had any leaks. I assume Tom had new gaskets cut from the correct material for his.

Nope. He marked the inspection plate before pulling them off. After cutting the parts that broke off out of the middle of the hole, he just replaced the plate with the same rubber gasket. Dry. Well, that's only half true because he never took the old one off. No leaks.

If I had known it would be THAT diddly-dang easy, I might have attempted it myself. But hey... Hindsight is always 20/20 and during the run up to deciding to hire a pro to do it, I could only imagine the worst case scenario - 100 gallons of diesel fuel oil spilling into the bilge with no way to stop it. I had already bought a few "form-a-gasket" sealers that are fuel compatible thinking I was going to have to gunk the crap out of in. Surprisingly enough, THAT was the only colossal waste of money. :banghead:

We only had one port, but each tank really could use three to get to every corner by hand. Nevertheless, Craig and Jed had a plan and it appeared to have worked. If it were me, get an air-powered body saw from Sears to cut the holes. It's like a jigsaw, but handheld like a dye-grinder and way easier to handle, and therefore more accurate, than a regular jigsaw. The only reason to be cutting into your tanks is to clean them, so I wouldn't worry about metal bits. They'll come out with the cleaning. :)

Tom-
 
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...If it were me, get an air-powered body saw from Sears to cut the holes. It's like a jigsaw, but handheld like a dye-grinder and way easier to handle, and therefore more accurate, than a regular jigsaw...Tom-

What a great idea. :thumb: Thanks.
 
While anything CAN happen, you would be surprised how few if any would actually land inside the tank with a couple of well placed magnets and bees wax. Especially if using a hole saw at slow rpm.
The magnet will not work on an aluminum or plastic tank.
 
tank cleaning

great Post. Very informative! Thanks!
 
You're welcome. Thanks for going back and taking a look. ;o)

Tom-
 
Our previous boat did not have inspection ports. We had two stainless steel tanks and every couple of years would run them down to 25% of capacity. We had an extremely large filter/sparator manifold with a high capacity 12volt fuel pump on a plywood frame. We vacuumed one tank through the filter into the other tank then reversed the process. We'd repeat the cycle 3-4 times. It worked well for 15 years.
 
NE Fl FuelPolishing

I've decided to have the existing diesel in my trawler "polished". Is this the same as tank cleaning?
 
No. Fuel polishing is the act of pumping your fuel out of your tank, then through a filter (or multiple filters) and back into your tank. You will end up with clean-ish fuel, but if your tanks are dirty, it will not clean them very well. Some fuel polishing rigs have a strong return stream that can knock down some gunk, but there is no way to get it all. TBH, I might have been ok with a thorough fuel polishing if the person knew what they were doing (e.g. Craig), but I have had the boat for three years and had not opened the tanks. I wanted to know for sure what was going on in there. So I am glad I did it.

I would actually say this to you. If you can afford it and don't have a ton of fuel in your tanks (assuming you are unable to open a port and see inside), I would say to get someone to scrub your tanks the best they can with the polishing rig and then empty your tanks and put in new fuel. When Craig showed my my fuel after polishing, it still looked pretty bad.

Tom-
 
I dont know how I missed this post previously but I agree- great post!!
 

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